Peter Foster is the Telegraph's US Editor based in Washington DC. He moved to America in January 2012 after three years based in Beijing, where he covered the rise of China. Before that, he was based in New Delhi as South Asia correspondent. He has reported for The Telegraph for more than a decade, covering two Olympic Games, 9/11 in New York, the 2004 Boxing Day tsunami, the post-conflict phases in Afghanistan and Iraq and the 2011 Fukushima disaster in Japan.

Why Chris Christie's presidential ambitions could be swimming with the fishes

Christie repeated his denials that he knew anything about the bridge closure which caused massive traffic snarl-ups, and announced he was firing the aide who (it emerged yesterday) was responsible for the vindictive punishment of a local Democrat mayor who refused to endorse Christie during last year's gubernatorial re-election race.

On the surface, this was the kind of bravura performance for which the straight-talking pol is well known, but when it comes to his chance in the 2016 presidential race, it exposed Christie's strengths and weaknesses in almost equal measure.

On the plus side, Christie has a believable demeanour. His trick is to put you in the room, to take the viewer into this confidence.

So, he explains that was on his iPad towelling down after his morning workout when he first heard that that his staff had lied to him and ordered the bridge shutdown as an act of political vindictiveness. Christie explained he was "humiliated". He was "crushed". He was "saddened".

Similarly, he also detailed how four weeks ago, before going into a press conference, he had hauled in every member of his staff and given them an hour to come clean if they knew anything about the bridge closure. They all said "no", says Christie, so he went out and told the world he and his office were innocent.

The George Washington Bridge in New York (Photo: Reuters)

The problem for Christie is that this kind of straight-talk may work for today, but it may not be not enough to save him, or more accurately, save his presidential ambitions.

Even if nothing more emerges to show that Christie new about the closures – which would be a kill-shot even to his governorship – the danger is that Christie risks suffering death by a thousand cuts, as each one of these episodes pigeonholes him as the Tony Soprano figure not fit to be in the White House.

He talks about his staff "like family" and jokes that "politics ain't beanbag", but those kinds of phrases only remind us of the underlying (political) charge against Christie – that he's a score-settling bully-boy unfit to be president.

And this storyline is not going away. Local Democrats, who have been bested and berated by Christie over the last five years, are going to spin out the state-level enquiry into what happened, trawling through thousands of pages of documents and endless witnesses.

Then there is the threat of federal and congressional enquiries, all of which will keep uppermost in the public mind not just questions marks over how Christie ran his administration, but the over-arching meme of New Jersey, with pols and 'bosses' that risks, drip by drip, slowly poisoning the well for Christie.

Presidential politics is really about big-picture, impressionistic, character-based assessments of the public, the vast majority of whom will not follow the details of this story. For many voters real scrutiny of the candidates won't begin until that first presidential debate in the autumn of 2016, and even then the impressions will be superficial.

Christie's problem was that even before this blew up, there were question marks over whether his brand of New Jersey politics which relied on locals deals and delivery (say to the Hispanic community, or a particular county) could ever translate nationally.

Soothing southerners play well (Carter, Clinton, George W Bush in his guise as folksy Texan) but finger-wagging northeasterners? Less so.

This scandal shines a spotlight on very aspect of Chris Christie's political personality that required the most careful handling.

This was to be a big year for Christie. He has the chairmanship of the Republican Governor's Association and 2014 mid-term elections season that would have provide a perfect platform to build his national profile and credentials as a politician who could fix a broke Washington and deliver real change – as opposed to the wishy-washy chimera promised by Mr Obama.

But right now, it's hard to see many Republicans wanting Christie out on the stump with them now, and difficult to see how Christie can switch off the drip-feed of stories that his Democrat opponents will do everything in their power to highlight.

It's premature to write Christie off completely, but today's performance – all two hours of it – deepens questions over whether that Noo Joisy style of his won't get old. And fast.